package com.f6.utils;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateUtils {
    static final String formatPattern = "yyyy-MM-dd";

    static final String formatPattern_Short = "yyyyMMdd";
    
    static final String formatPattern_full = "yyyy-MM-dd HH:mm:ss";

    /**
     * 获取当前日期
     * 
     * @return
     */
    public static String getCurrentDate() {
	SimpleDateFormat format = new SimpleDateFormat(formatPattern_full);
	return format.format(new Date());
    }

    /**
     * 获取制定毫秒数之前的日期
     * 
     * @param timeDiff
     * @return
     */
    public static String getDesignatedDate(long timeDiff) {
	SimpleDateFormat format = new SimpleDateFormat(formatPattern);
	long nowTime = System.currentTimeMillis();
	long designTime = nowTime - timeDiff;
	return format.format(designTime);
    }

    /**
     * 
     * 获取前几天的日期
     */
    public static String getPrefixDate(String count) {
	Calendar cal = Calendar.getInstance();
	int day = 0 - Integer.parseInt(count);
	cal.add(Calendar.DATE, day); // int amount 代表天数
	Date datNew = cal.getTime();
	SimpleDateFormat format = new SimpleDateFormat(formatPattern);
	return format.format(datNew);
    }

    /**
     * 日期转换成字符串
     * 
     * @param date
     * @return
     */
    public static String dateToString(Date date) {
	SimpleDateFormat format = new SimpleDateFormat(formatPattern);
	return format.format(date);
    }

    /**
     * 字符串转换日期
     * 
     * @param str
     * @return
     */
    public static Date stringToDate(String str) {
	// str = " 2008-07-10 19:20:00 " 格式
	SimpleDateFormat format = new SimpleDateFormat(formatPattern_full);
	if (!str.equals("") && str != null) {
	    try {
		return format.parse(str);
	    } catch (ParseException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	    }
	}
	return null;
    }

    // java中怎样计算两个时间如：“21:57”和“08:20”相差的分钟数、小时数 java计算两个时间差小时 分钟 秒 .
    public void timeSubtract() {
	SimpleDateFormat dfs = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	Date begin = null;
	Date end = null;
	try {
	    begin = dfs.parse("2004-01-02 11:30:24");
	    end = dfs.parse("2004-03-26 13:31:40");
	} catch (ParseException e) {
	    e.printStackTrace();
	}

	long between = (end.getTime() - begin.getTime()) / 1000;// 除以1000是为了转换成秒

	long day1 = between / (24 * 3600);
	long hour1 = between % (24 * 3600) / 3600;
	long minute1 = between % 3600 / 60;
	long second1 = between % 60;
	System.out.println("" + day1 + "天" + hour1 + "小时" + minute1 + "分" + second1 + "秒");
    }
}
